/*
  将下面异步代码使用 Promise 的方法改进
  尽量用看上去像同步代码的方式
  setTimeout(function () {
    var a = 'hello'
    setTimeout(function () {
      var b = 'lagou'
      setTimeout(function () {
        var c = 'I ♥ U'
        console.log(a + b +c)
      }, 10)
    }, 10)
  }, 10)
*/

function a(msg) {
  return new Promise(function(resolve,reject){
      setTimeout( () => {
          resolve(msg);
      },10)
  });
}

a().then(() => {
  return a('hello')
}).then(value =>{
  return a(value+'lagou')
}).then (value => {
  return a(value+'I Love U')
}).then (value=> {
  console.log(value)
})

